Exergy Analysis of the Steam Generation System to Explore the Potential for Optimizing Energy Consumption

Document Type : Research Article

Authors

• I. Golpour
• P. Ahmadi Moghaddam
• A. M. Nikbakht

Department of Mechanical Engineering of Biosystems, Urmia University, Urmia, Iran

https://doi.org/10.22067/jam.2021.57932.0

Abstract

Introduction
Steam generation system is a crucial and essential part of food industries which generates and distributes steam for consumption in domestic production units. Energy analysis based on the first law of thermodynamics was employed as the basic approach to assess energy systems. However, the energy approach does not provide information on the degradation of the energy quality occurring within energy systems and is, therefore, insufficient for sustainable design or optimization goals. Nevertheless, exergy analysis based on both the first and second laws of thermodynamics can overcome shortcomings of energy analysis. In the present study, the performance of equipment of the steam generation system in Pakdis’s juice production Company located in Urmia is investigated. Owing to the energy and exergy analyses, the sites with the highest loss of exergy are identified as the critical points of the process.
Materials and Methods
In this study, the steam generation unit of a juice production company located in Urmia, West Azarbaijan province in Iran was exergetically analyzed. Using mass, energy, and exergy balances for each component of the unit, the thermodynamic objective functions including the exergy efficiency, exergy destruction rate, exergy loss rate, and the potential improvement rate were assessed. After data acquisition, energy and exergy analysis of this unit was achieved by solving the related equations with the help of thermodynamic properties along with programming in EES software package.
Results and Discussion
The results showed that the highest exergy efficiency of 98.44% was assigned to the steam distributor (O) of the unit with a potential improvement rate of 1.51 kW and an exergy loss rate of 68.80 kW, as well as the pump (M) before the fourth boiler with an exergy efficiency of 19.69%, had the lowest value of exergy efficiency. The values of 12.55 and 11.93 kW were obtained for the exergy destruction rate and its potential improvement rate, respectively. The highest exergy destruction rate of the unit was for the first boiler with a value of 12391.80 kW, with an efficiency of 19.55% and a potential improvement rate of 10295.26 kW.
Conclusion
With regard to the energy and exergy analyses of the steam production system, more than 98% of the exergy destruction rate of the entire steam generation system was assigned to boilers, which had a major contribution to the exergetic efficiency of the system. The highest percentage of potential improvement was related to the first boiler and also the third boiler had the highest exergy loss rate, although the lowest exergy loss rate was the expansion tank of the system. In general, this study demonstrated the importance of exergy analysis for detecting the system components with the highest exergy destruction, which can be a breakthrough to identify these components and provides suitable solutions to improve the overall exergy efficiency of the steam-generating system.

Keywords

• Exergetic efficiency
• Exergy destruction rate
• Exergy potential improvement rate
• Steam generation system

20.1001.1.22286829.1401.12.2.2.4

Open Access

©2021 The author(s). This article is licensed under Creative Commons Attribution 4.0 International License (CC BY 4.0), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source.

References

1. Ahmadi, G. R., and D. Toghraie. Energy and exergy analysis of montazeri steam power plant in iran, Renewable and Sustainable Energy Reviews 56: 454-463.
2. Çamdali, Ü., and M. Tunç. Exergy analysis and efficiency in an industrial AC electric ARC furnace. Applied Thermal Engineering 23: 2255-2267.
3. Colak, N., Z. Erbay, and A. Hepbasli. Performance assessment and optimization of industrial pasta drying. International Journal of Energy Research 37: 913-922.
4. Dincer, I. and Y. A. Cengel. Energy, entropy and exergy concepts and their roles in thermal engineering. Entropy 3: 116-149.
5. Dowlati, M., M. Aghbashlo, and M. M. Soufiyan. Exergetic performance analysis of an ice-cream manufacturing plant: a comprehensive survey. Energy 123: 445-459.
6. Gümüş, M., and M. Atmaca. 2013. Energy and exergy analyses applied to a CI engine fueled with diesel and natural gas. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 35: 1017-1027.
7. Hepbasli, A. 2010. A review on energetic, exergetic and exergoeconomic aspects of geothermal district heating systems (GDHSs). Energy Conversion and Management 51: 2041-61.
8. Holman, J. P. 2001. Analysis of experimental data. In: Holman JP, editor. Experimental methods for engineers. Singapore: McGraw-Hill: 48-143.
9. Jokandan, M. J., M. Aghbashlo, and S. S. Mohtasebi. 2015. Comprehensive exergy analysis of an industrial-scale yogurt production plant. Energy 93: 1832-1851.
10. Kotas, T. J. 1995. The Exergy Method of Thermal Plant Analysis. Krieger Publishing Company.
11. Kotas, T. J. 2012. The Exergy Method of Thermal Plant Analysis. Exergon Publishing Company.
12. Mborah, C., and E. K. Gbadam. 2010. on the energy and exergy analysis of a 500 kW steam power plant at benso oil palm plantation (bopp). Research Journal of Environmental and Earth Sciences 2: 239-244.
13. Moran, J., and N. Talwar. 1994. Fundamentals of Engineering Thermodynamics, 3nd Edition, McGraw Hill, New Yirk.
14. Rosen, M. and I. Dincer. 2001. Exergy as the Confluence of Energy, Environment and Sustainable development. Exergy, an International Journal 1: 3-13.
15. Soufiyan, M. M., A. Dadak, S. S. Hosseini, F. Nasiri, M. Dowlati, M. Tahmasebi, and M. Aghbashlo. 2016. Comprehensive exergy analysis of a commercial tomato paste plant with a double-effect evaporator. Energy 111: 910-922.
16. Szargut, J., D. R. Morris, and F. R. Steward. 1988. Exergy Analysis of Thermal, Chemical and Metallurgical Processes. Hemisphere Publishing Corporation., New York.
17. Todorović, M. N., D. S. Živković, M. V. Mančić, and G. S. Ilić. 2014. Application of energy and exergy analysis to increase efficiency of a hot water gas fired boiler. Chemical Industry & Chemical Engineering Quarterly 20 (4).
18. Utlu, Z., and A. Hepbasli. 2007. A review on analyzing and evaluating the energy utilization efficiency of countries. Renewable and Sustainable Energy Reviews 11: 1-29.
19. Ziaaddini, A., H. Mortezapour, M. Shamsi, and A. Sarafi. 2017. Energy and exergy analysis of a greenhouse heating system equipped with a parabolic trough concentrator and a flat-plate solar collector. Journal of Agricultural Machinery 9 (2): 439-453. (In Persian). DOI: 22067/jam.v9i2.65174.